https://mp.weixin.qq.com/s/3DRBX9Wb-OA-_NIfPXZjcw
前言
程池ThreadPoolExecutor
,
而用的是Spring Boot项目,可以用Spring提供的对ThreadPoolExecutor
封装的线程池
-
ThreadPoolTaskExecutor
,直接使用注解启用
ThreadPoolTaskExecutor 使用步骤
先创建一个线程池的配置,让Spring Boot加载,用来定义如何创建一个ThreadPoolTaskExecutor
,
要使用@Configuration
和@EnableAsync
这两个注解,表示这是个配置类,并且是线程池的配置类
1. 配置类
@Configuration
@EnableAsync
public class ExecutorConfig {
private static final Logger logger = LoggerFactory.getLogger(ExecutorConfig.class);
@Value("${async.executor.thread.core_pool_size}")
private int corePoolSize;
@Value("${async.executor.thread.max_pool_size}")
private int maxPoolSize;
@Value("${async.executor.thread.queue_capacity}")
private int queueCapacity;
@Value("${async.executor.thread.name.prefix}")
private String namePrefix;
@Bean(name = "asyncServiceExecutor")
public Executor asyncServiceExecutor() {
logger.info("start asyncServiceExecutor");
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
//配置核心线程数
executor.setCorePoolSize(corePoolSize);
//配置最大线程数
executor.setMaxPoolSize(maxPoolSize);
//配置队列大小
executor.setQueueCapacity(queueCapacity);
//配置线程池中的线程的名称前缀
executor.setThreadNamePrefix(namePrefix);
// rejection-policy:当pool已经达到max size的时候,如何处理新任务
// CALLER_RUNS:不在新线程中执行任务,而是有调用者所在的线程来执行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
//执行初始化
executor.initialize();
return executor;
}
}
2. properties文件
@Value
是我配置在application.properties
,可以参考配置,自由定义
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>
> <https://github.com/YunaiV/onemall>
# 异步线程配置
# 配置核心线程数
async.executor.thread.core_pool_size = 5
# 配置最大线程数
async.executor.thread.max_pool_size = 5
# 配置队列大小
async.executor.thread.queue_capacity = 99999
# 配置线程池中的线程的名称前缀
async.executor.thread.name.prefix = async-service-
创建一个Service接口,是异步线程的接口
public interface AsyncService {
/** * 执行异步任务 * 可以根据需求,自己加参数拟定,我这里就做个测试演示 */
void executeAsync();
}
3. 使用 异步线程,controller
实现类
@Service
public class AsyncServiceImpl implements AsyncService {
private static final Logger logger = LoggerFactory.getLogger(AsyncServiceImpl.class);
@Override
@Async("asyncServiceExecutor")
public void executeAsync() {
logger.info("start executeAsync");
System.out.println("异步线程要做的事情");
System.out.println("可以在这里执行批量插入等耗时的事情");
logger.info("end executeAsync");
}
}
将Service层的服务异步化,在executeAsync()
方法上增加注解@Async("asyncServiceExecutor")
,
-
asyncServiceExecutor
方法是前面ExecutorConfig.java 中的方法名,
- 表明
executeAsync
方法进入的线程池是asyncServiceExecutor
方法创建的
接下来就是在Controller里或者是哪里通过注解@Autowired
注入这个Service
@Autowired
private AsyncService asyncService;
@GetMapping("/async")
public String async() {
asyncService.executeAsync();
System.out.println("我响应了");
return "async";
}
4. 基本测试
用postmain或者其他工具来多次测试请求一下
我响应了
2022-01-20 11:45:53.001 INFO 12256 --- [async-service-1] c.e.demoxin2.executor.AsyncServiceImpl : start executeAsync
异步线程要做的事情
可以在这里执行批量插入等耗时的事情
2022-01-20 11:45:54.941 INFO 12256 --- [async-service-1] c.e.demoxin2.executor.AsyncServiceImpl : end executeAsync
通过以上日志可以发现,[async-service-]
是有多个线程的,显然已经在我们配置的线程池中执行了,并且每次请求中,controller的起始和结束日志都是连续打印的,表明每次请求都快速响应了,而耗时的操作都留给线程池中的线程去异步执行;
虽然我们已经用上了线程池,但是还不清楚线程池当时的情况,有多少线程在执行,多少在队列中等待呢?这里我创建了一个ThreadPoolTaskExecutor的子类,在每次提交线程的时候都会将当前线程池的运行状况打印出来
5. 线程类 扩展
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.util.concurrent.ListenableFuture;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;
/** * @Author: ChenBin * @Date: 2018/7/16/0016 22:19 */
public class VisiableThreadPoolTaskExecutor extends ThreadPoolTaskExecutor {
private static final Logger logger = LoggerFactory.getLogger(VisiableThreadPoolTaskExecutor.class);
private void showThreadPoolInfo(String prefix) {
ThreadPoolExecutor threadPoolExecutor = getThreadPoolExecutor();
if (null == threadPoolExecutor) {
return;
}
logger.info("{}, {},taskCount [{}], completedTaskCount [{}], activeCount [{}], queueSize [{}]",
this.getThreadNamePrefix(),
prefix,
threadPoolExecutor.getTaskCount(),
threadPoolExecutor.getCompletedTaskCount(),
threadPoolExecutor.getActiveCount(),
threadPoolExecutor.getQueue().size());
}
@Override
public void execute(Runnable task) {
showThreadPoolInfo("1. do execute");
super.execute(task);
}
@Override
public void execute(Runnable task, long startTimeout) {
showThreadPoolInfo("2. do execute");
super.execute(task, startTimeout);
}
@Override
public Future<?> submit(Runnable task) {
showThreadPoolInfo("1. do submit");
return super.submit(task);
}
@Override
public <T> Future<T> submit(Callable<T> task) {
showThreadPoolInfo("2. do submit");
return super.submit(task);
}
@Override
public ListenableFuture<?> submitListenable(Runnable task) {
showThreadPoolInfo("1. do submitListenable");
return super.submitListenable(task);
}
@Override
public <T> ListenableFuture<T> submitListenable(Callable<T> task) {
showThreadPoolInfo("2. do submitListenable");
return super.submitListenable(task);
}
}
如上所示,showThreadPoolInfo方法中将
-
任务总数、已完成数、活跃线程数,队列大小都打印出来了,
-
然后Override了父类的execute、submit等方法,
-
在里面调用showThreadPoolInfo方法,
-
这样每次有任务被提交到线程池的时候,都会将当前线程池的基本情况打印到日志中;
修改ExecutorConfig.java
的asyncServiceExecutor
方法,
将
`ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor()`
改为
`ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor()`
6. 再次启动该工程测试
2022-01-20 13:45:45.227 INFO 21636 --- [nio-8080-exec-1] c.e.d.e.VisiableThreadPoolTaskExecutor : 线程打印:async-service-, 2. do submit,taskCount [0], completedTaskCount [0], activeCount [0], queueSize [0]
2018-07-16 22:23:32.496 INFO 14088 --- [nio-8087-exec-7] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [3], completedTaskCount [3], activeCount [0], queueSize [0]
这说明提交任务到线程池的时候,调用的是submit(Callable task)这个方法,当前已经提交了3个任务,完成了3个,当前有0个线程在处理任务,还剩0个任务在队列中等待,线程池的基本情况一路了然;